[GPSNavX]

For an AIS receiver I like these units ..

http://www.milltechmarine.com/Comar-AIS-...p_149.html

http://www.milltechmarine.com/AMEC-CYPHO...p_143.html

Both can connect to your Mac with a USB cable. The later even offers a model with a built in GPS receiver.

What instrumentation did you want to connect to the Multiplexer? All Shipmodul units will work, but need to know what you want achieve.